Thermo-electric couple.



* sTATwENT O EzEcHiEL wizmrnA-Un, or LYNN, MASSACHUSETTS, ASSIG-NOR T0GENERAL ELECTRIG coHPANY, A CORPORATION or NEW YORK.

@nsemo-Em'cmmc downs.

Specification of Letters Patent.

Patented Nov. 25, 1913.

ipplieati'n in Qctober 27, 1909. Serial No. 524,945.

Be it known that I, EZECHIEL WEIN'IRAUB; a citizen of the United States,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Thermo-Electric Couples, of whichthe following is a specification.

My present invention comprises an improved electric couple}, suitablefor use as a source of current, or for other purposes, and including asa part thereof an element consisting wholly or in part of boron.

Moissan and other chemists describe boron to be a brownish powder,practically nonconductive for electricity, and vaporizable withoutfusion. After a long research I have found that pure boron is a fairconductor of electricity, can be fused to a dense body, and has anegative temperature resistance coefiicient of a magnitude withoutprecedent among chemical elements. I have also discovered that boron iswell adapted for use as an element in a thermo-electric couple. For thispurpose the boron need not be chemically pure, but may have associatedwith it carbon, silicon, magnesium, aluminum or other material capableof lowering its specific resistance without materially changing itsthermo-electric power.

Conductors of boron, or of boron associated with carbon suitable for useaccording to the present invention, may be made by reducing boronchlorid with hydrogen in the presence of a high voltage alternatingcurrent are maintained between watercooled copper electrodes. The methodand apparatus for carrying out this operation are fully described by mein my co-pending application, Serial No. 524,939 of even date. In suchan apparatus some of the reduced boron fuses on the electrodes and growsinto beads and rods. In this form it can be used directly as an elementof the thermo-couple. Some of the reduced pure boron is thrown out onthe walls of the arc chamber in a finely divided condition. This powderis pressed into sticks, either with or without the addition of carbon,or other material, and subsequently fused by being made the electrode ofa high potential are operating inhydrogen. This latter process is fullyde scribed by me in my co-pending application,

Serial No. 924,947 of even date. The sticks can also be fused to a densebody in a mer cury-vapor arc.

According to another method of manufacture, the thermo-electric elementcom posed of boron, or of boron associated with another material,suitable for use in a thermo couple, can be made by reducing an ex cessof boric anh drid with magnesium. The resulting prod uct consists ofmagnesium borid and boron suboxid, and can be made to yield fused,substantially pure boron by pressing it into a stick, preheating it in avacuum furnace to drive out some of the impurities and make it partiallyconductive, and then heating the stick as an electrode for a highpotential alternating current are operating in hydrogen at a pressure ofabout five inches of mercury, or by heating'it in a mercury-vapor are.This treatment will drive out most of the magnesium or oxygen, and ifcarried to a suflicient temperature will sinter the boron into a densebody. If carbon, or other element is desired in the ultimate product, itcan be added to the powdered magnesium borid or suboxid in theproportions desired in the final product. 1

The other element of the thermo-electric couple consists of iron,nickel, or of other materials well known for this purpose. These otherelements can be connected with the boron conductor by casting the sameabout one end of the boron rod, bar or sheet. A junction is maintainedin a heated condition, and the free ends are cooled, as by thecirculation of cold air or water, or by means and methods well known inthe art. Such a couple is useful not only as a source of current,because of its strong thermo-electric properties, but also because ofthe rectifying action which it exerts when connected as a part of thecircuit carrying current at low voltages. The thermo-electromotive forceassists in impressing electromotive force in one direction and opposesit in the other direction, so that unsymmetrical current results. Thischaracteristic makes the couple valuable for use as an asymmetricconductor insystems of Wireless telcgraphy. and the like asdescribed andclaimed in my application, Serial No. 524,946, of even date herewith.

What I claim as new, and desire to secure 5 by Letters Patent of theUnited States is:

1. A thermo-electric couple, one element of which consists essentiallyof boron.

2. A thermo-electric couple, one element of which is composed of boronassociated 10 with carbon.

3. A thermo-electric couple, one member of which is constructed of afused body, consisting largely of boron.

Patent Otfice.

[SEAL] w my hand this 26th day of October, 1909.

EZECHIEL WEINTRAUB. Witnesses:

JOHN A. MCMANUS, J r., CHARLES A. BARNARD.

It is hereby certified that in Letters Patent No. 1,079,621, grantedNovember 25,

1913, upon the application of Ezechiel Weintraub, of Lynn,Massachusetts, for an improvement in Thermo-lllectric Couples, an errorappears in the printed specification requiring correction as follows:Page 1, line 54, for the serial number 924,947, read 521L9-l7 and thatthe said Letters Patent should he read with this correction therein thatthe same may conform to the record of the casein the Signed and sealedthis 6th day of January, A. D., 1914.

. J. T. NEWTON,

Acting Commissioner of Patente.

